Method for production of a gas-tight ducting for a contact through a wall and device for ducting an electrical contact through a wall

ABSTRACT

The invention relates to a method for production of a gas-tight ducting for a contact ( 4 ) through a wall ( 12 ), in particular in a fuel tank and a device for said ducting. According to the method, the contact is placed in a tool form ( 1 ), in which a partial region of the contact ( 4 ) is surrounded by a cover ( 9 ) made from an insulating material. The cover ( 9 ) is then directly or indirectly connected to the wall ( 12 ). According to the invention, the device embodies the contact ( 4 ) and the cover ( 9 ) thereof as a unitary construct.

The invention relates to a method for production of a gas-tight ductingfor a contact through a wall, in particular a wall of a fuel tank.Furthermore, the invention relates to a device for ducting an electricalcontact through a wall, in particular a wall of a fuel tank.

In ductings known from practice, contacts are generally pressed throughthe wall, which is manufactured from plastic, or through a supportconnected to the wall, so that one end of the contacts protrudes on eachside of the wall. Electric leads can then be connected to the contactson both sides of the wall.

A disadvantage of the known device is that the connection of thecontacts to adjacent regions of the wall or of the support can be sealedonly with very great difficulty. In the case of the device provided forthe fuel tank, fuel vapors can diffuse through between the contacts andadjacent regions of the support or of the wall. This enables fuel topass from the fuel tank into the environment.

The invention is based on the problem of developing a method of the typementioned at the beginning in such a manner that the contacts which oneto be ducted through the wall can be sealed in a particularly reliablemanner. Furthermore, a device of the type mentioned at the beginning inwhich the contacts are reliably sealed with respect to adjacent regionsis to be provided.

The problem mentioned first is solved according to the invention by thecontact being placed into a mold and a partial region of the contactbeing surrounded in the mold by a covering made from an insulatingmaterial, and by the covering then being connected indirectly ordirectly to the wall.

By this means, a preassemblable, constructional unit comprising contactand insulator is produced in the mold. The surrounding of the contact inthe mold makes it possible to ensure that the connection between thecontact and the covering is particularly leakproof. A suitable methodfor manufacturing the covering makes it possible for the connection ofthe contact to the covering to be designed with a cohesive materialjoint.

In one advantageous refinement of the invention, the contact is producedby the mold by the contacts being supplied to the mold as stripmaterial, for example, and not being detached or punched out until themold is closed. A partial region of the contact is then surrounded bythe covering in the mold.

According to one advantageous development of the invention, the coveringcan be manufactured from ceramic if the covering is produced bysintering. This enables the covering to have high temperature stability.

According to another advantageous development of the invention, theconnection of the contact to the covering with a cohesive material jointcan be ensured in a simple manner if the covering is produced bycasting. This enables the covering to be manufactured from plastic orglass.

The second problem mentioned, namely the provision of a device in whichthe contacts are reliably sealed with respect to adjacent regions, issolved according to the invention by the contact and a covering whichsurrounds a partial region of the contact and is made from an insulatingmaterial being designed as a constructional unit.

This design makes it possible to reliably avoid leakages between thecontact and adjacent regions. For assembly purposes, the unit can beinserted on a support, which is to be connected to the wall, or can beinserted directly in the wall. The material of the covering can beselected in such a manner that it can simply be sealed to the support orthe wall.

According to one advantageous development of the invention, the coveringcan be fitted in the wall in a particularly simple manner if thecovering has a conical form. The wall or the support thus requires aconical recess, into which the covering is pressed. Moreover, thiscompensates for tolerances between the recess in the wall or the supportand the covering.

According to another advantageous development of the invention, acontribution is made to further increasing the reliability of thesealing of the contact by the covering if the contact and the coveringare connected directly to each other with a cohesive material joint. Thedirect connection of the contact to the covering means that an adhesiveor the like is not required for sealing purposes.

According to another advantageous development of the invention, theconnection of the contact to the covering has good endurance if thecontact has a cross-sectional change in the region of the covering.

The invention permits numerous embodiments. To further clarify its basicprinciple, one of these is illustrated in the drawing and will bedescribed below. In the drawing

FIG. 1 shows a contact together with a mold for carrying out the methodaccording to the invention,

FIG. 2 shows a device according to the invention with a constructionalunit comprising a contact according to FIG. 1 and a covering,

FIG. 3 shows the constructional unit from FIG. 2 after it has beenfitted in a wall.

FIG. 1 shows a mold 1 with two mold parts 2, 3 and a contact 4. The mold1 may, for example, be a casting mold or a sintering mold. The moldparts 2, 3 have a respective recess 5, 6 for holding the ends of thecontact 4. One of the mold parts 2 has a conical recess 7. The othermold part 3 has openings 8 in which to place the material of a covering9, which is illustrated in FIG. 2. The contact 1 has two cross-sectionalchanges 10 which, when the contact 4 is inserted into the mold 1, aresituated within the conical recess 7. To manufacture the covering 9which is illustrated in FIG. 2, the contact 4 is first of all insertedinto one of the mold parts 2, 3 and the mold 1 is put together. Thematerial forming the covering 9 is then introduced through the openings8 into the conical recess 7 of the mold 1. This material can beintroduced in a powdery, liquid or pasty state. The covering 9 ismanufactured, for example, by sintering or by casting.

FIG. 2 shows the contact 4 together with the covering 9 after removalfrom the mold 1 from FIG. 1. The covering 9 forms a constructional unitwith the contact 4. As illustrated in FIG. 3, this constructional unitcan be pressed into a correspondingly designed recess 11 in a wall 12 orcan be connected to the latter indirectly or directly with a cohesivematerial joint, for example by the action of heat.

1. A device for ducting a contact (4) through a wall of a fuel tank,characterized in that contact elements which are designed only for theconnection of leads which lead away and a conically shaped covering (9)which is cohesively connected to the contact and is made from aninsulating material are designed as a constructional unit to be bondeddirectly to the wall of the fuel tank, and in that the contact (4) has across-sectional change (10) in the region of the covering (9) and inthat the contact (4) and the contact elements are designed as asingle-piece element, the ends of the single-piece element protrudingout of the covering (9) and forming the contact elements.